Tankless Hot Water Systems

Electric tankless hot water systems can save both money and energy when compared to traditional tank-style water heaters.


By Steve Panosian 

A LITTLE OVER 10 YEARS AGO, WE REPLACED A HOME HEATING OIL BOILER WITH A PROPANE SYSTEM when we were forced to rebuild our home’s lower-level, post Hur­ricane Irene. We chose the new propane system because it was a wall-mounted four-foot off-the-floor compact-size boil­er that also featured on-demand hot water. It made sense at the time considering a cleaner burning fuel and never worry­ing about the new boiler getting destroyed by a future flood.

After living with this system for over 10 years, our only main­tenance is the annual negligible cost tune-up that involves cleaning and new ignition electrodes.

In revisiting the tankless hot water on-demand technology and industry advancements, while propane and natural gas systems have been prominent, electric on-demand tankless hot water is a no-brainer consideration for those investing in a performance home featuring solar/geothermal energy, power storage, and water filtration and purification.

Electric tankless hot water systems 

Also known as on-demand water heaters, these are a type of water heating system that heats water as it is needed, than storing it in a tank and keeping it hot all the time. There are many benefits besides running on cleaner energy:

EFFICIENCY: Electric tankless hot water systems are highly efficient, as they only use energy when hot water is needed. This means that they can save energy compared to tradition­al tank-style water heaters.

CAPACITY: The capacity of an electric tankless hot water system refers to the maximum flow rate of hot water it can produce. The capacity when choosing a tankless hot water system must meet household demand needs, especially during peak usage periods.

SIZE AND INSTALLATION: Electric tankless hot water sys­tems are typically smaller in size than tank-style water heat­ers, which makes them easier to install in smaller spaces. It’s likely code — as well as strongly recommended — that a dedicated electrical circuit is considered when planning the installation of a tankless hot water system.

COST: The cost of an electric tankless hot water system is typically higher than that of a traditional tank-style water heater, but the savings in energy and space can offset the initial investment over time.

MAINTENANCE: Electric tankless hot water systems require less maintenance than tank-style water heaters, as they have fewer parts that can wear out or break down. However, it’s still important to have the system regularly inspected and serviced to ensure it is working efficiently and safely.

ENVIRONMENTAL IMPACT: Electric tankless hot water sys­tems do not produce emissions, as they do not burn fuel to heat water. This makes them a more environmentally friendly option compared to tank-style water heaters that use natural gas or propane.

WATER FILTRATION AND PURIFICATION: The peace of mind benefit of knowing the household’s water is safe and pure will also extend the usable life of any hot water solution especially if a mineral filter stage is introduced at the POE.

How they work

Electric hot water on-demand systems work by heating water as it passes through the unit’s heating element, providing hot water without the need for a continuously heated hot water tank. When hot water is demanded, cold water flows into the unit through a heating element, powered by electricity, and heats the water. The heated water then flows to the faucet or appliance demanding hot water.

The other side benefit of on-demand hot water, the unit will continue to provide a continuous supply of hot water without running out of water. When the water flow ceases, the heat­ing element will stop heating the water, conserving energy.

Energy efficiency is a key advantage of electric hot water on-demand systems since they only heat water when it’s needed as opposed to traditional hot water storage tanks, which continually heat and reheat water throughout the day. Smart thermostats are designed to be set for vacation or away modes that adjust home heating and cooling tempera­tures. On-demand hot water systems will remain off and do not require an ‘away’ mode.

Popular leading brands

There are many manufacturers that produce high-quality electric tankless water heaters. Some of the top brands in the market include:

RHEEM  A leading manufacturer of electric tankless water heaters and its products are known for their reliability and efficiency.

STIEBEL ELTRON  A German company that specializes in the production of electric tankless water heaters. Their products are known for their energy efficiency and durability.

ECOSMART  A U.S.-based company that produces a wide range of electric tankless water heaters. Their products are known for their energy efficiency, compact design and user-friendly controls.

RINNAI  A Japanese company that produces a wide range of tankless water heaters, including electric models. Their products are known for their high-quality construction, energy efficiency and advanced features.

BOSCH  Another German company that produces a range of tankless water heaters, including electric models. Their products are known for their durability, energy efficiency and ease of in­stallation.

While the “best” electric tankless water heater systems de­pend on specific needs and preferences, most contractors and consumers will likely rely on reviews from past installa­tions and reviews to determine which brand and model will work best.

Energy and cost savings

Clearly, electric tankless hot water systems can save both money and energy when compared to traditional tank-style water heaters because they only use energy when hot water is being used, which can result in significant energy savings over time.

In addition to energy savings, electric tankless water heat­ers can also save money in the long run because they have a longer lifespan than traditional tank-style water heaters. Tankless units are typically designed to last up to 20 years, compared to a typical lifespan of 10-15 years for traditional water heaters. So over time, the need to replace an elec­tric tankless water heater isn’t as frequent, which saves you money in replacement costs. However, it’s important to note that the initial cost of purchasing and installing an electric tankless water heater can be higher than a traditional water heater, so it’s a matter of weighing the financial benefits of the investment vs. reducing the reliance on energy sources with higher carbon footprints.

Manufacturer and trade publications

MANUFACTURER WEBSITES: Many manufacturers of on-demand hot water systems have websites that provide information about their products, including testimonials and expert opinions. For example, Rinnai, a manufacturer of tank­less water heaters, has a section on their website where they provide expert opinions and interviews with industry profes­sionals: .rinnai.us/experts-speak

TRADE PUBLICATIONS: There are a number of trade pub­lications in the plumbing and heating industry that cover on-demand hot water systems. These publications of­ten include interviews with industry experts and reviews of different products. Some examples include Plumbing & Mechanical Magazine, Contractor Magazine and Heating, Air Conditioning & Plumbing Magazine.

CONFERENCES AND EVENTS: Industry conferences and events often feature presentations and panel discussions with experts in the field. The International Builders’ Show, for ex­ample, is a large trade show that covers a range of topics re­lated to the building industry, including on-demand hot water systems.

PROFESSIONAL ASSOCIATIONS: Professional associations for plumbers, HVAC technicians, and builders may provide resources and expert opinions about on-demand hot water systems. Some examples include the Plumbing-Heating-Cool­ing Contractors Association, the National Association of Home Builders and the Air Conditioning Contractors of America.

While there are a number of expert opinions that can provide useful insights, it’s also important to consider factors such as the size of the household, the hot water needs, and the cost of different options when providing the decision-making data about which type of hot water system to install.